Thermal-pane window with liquid crystal shade

Abstract

A thermal-pane window unit having an electro-optical shade of adjustable transmittance is provided for reducing radiative heat transfer, as well as conductive transfer, between the exterior and interior of a building and, additionally, for presenting an attractive shaded window appearance. The invention utilizes a liquid crystal cell of selectable light transmittance in combination with a conventional dual pane heat insulating window. The liquid crystal material is preferably electro-optically responsive to a low voltage AC field.

What is claimed is: 
     
       1. A method for decreasing radiative and conductive heat transfer between the exterior and the interior of a building, comprising the steps of: (a) mounting within a window frame, a plurality of spaced window panes;   (b) delimiting between said window panes a first space providing a thermal break and a second space containing an electro-optical liquid crystal cell providing a selected light transmittance.   
     
     
       2. A method as recited in claim 1, comprising the step of adjusting said window panes to be substantially parallel. 
     
     
       3. A method as recited in claim 2, comprising the step of adjusting said window panes until the spacing therebetween is sequential. 
     
     
       4. A method as recited in claim 3, comprising the step of sealing said window panes to isolate the spaces therebetween. 
     
     
       5. A method as recited in claim 4, comprising the step of mounting a first of said window panes in said window frame in the outermost position toward the exterior facing side of said window frame. 
     
     
       6. A method as recited in claim 5, comprising the step of mounting a second of said window panes in said window frame parallel to and spaced from said first window pane in a position intermediate between the exterior facing and interior facing sides of said window frame, whereby the opposing faces of said first and second panes delimit a first space for a thermal conduction break. 
     
     
       7. A method as recited in claim 6, comprising the step of mounting a third of said window panes in said window frame in the innermost position toward the interior facing side of the frame means, whereby the opposing faces of the second and third window panes delimit a second space for containing an electro-optically responsive material. 
     
     
       8. A method as recited in claim 7, comprising the step of placing a liquid crystal material in the space between the opposing faces of the second and third window panes. 
     
     
       9. A method as recited in claim 8, comprising the step of depositing a transparent, electrically conductive film on each of the opposing faces of the second and third window panes. 
     
     
       10. A method as recited in claim 9 comprising the step of applying an electrical field between said conductive films and through said liquid crystal material of a selected field strength at least sufficient to exceed the threshold required to cause light scattering in said liquid crystal material.